The head louse (pediculus humanus capitit) infests roughly 2-3% of grade school children in the United States and England. The females, about 1/8 inch long, deposit approximately 270-300 eggs, most commonly on the hair above the ears and the back of the head near the base of the hair shaft. The eggs are cemented to the hair with a tenacious protein-like substance.
Head lice are capable of spreading disease. Specifically, head lice are vectors for staphylococcal skin infections, e.g., impetigo, furunculosis, and are also the principle method of transmission for typhus, trench fever, and relapsing fever.
Effective control of head lice can be obtained with a number of insecticides (termed pediculicides for this application), such as malathion, carbaryl, lindane, pyrethrins and piperonyl butoxide, and the synthetic pyrethrin analog permethrin. The most acceptable treatments involve shampoos which contain the pediculicide, some of which are prescription products (e.g., lindane). Some eggs, however, often survive the treatment.
Physical removal of the lice can be accomplished to a significant degree with hair washing followed by thorough brushing. Fine toothed nit combs, which are designed for removal of the nits anchored to the hair shaft, are not particularly effective in removing the eggs. If still alive, the eggs can lead to a full reinfestation of the hair. If dead, following pediculicide treatment, they can still represent a social embarrassment for both child and parent, with no absolute certainty that the nits are all dead and therefore potentially reinfesting.
Furthermore, children must be nit free to return to school even if a lice treatment is resident on the head. Therefore, efforts have recently been directed to develop products which are effective in unlocking the bond between the lice egg and the hair. One such product is marketed under the trademark STEP 2.RTM. by GenDerm as a lice egg removal kit. STEP 2.RTM. is a liquid treatment that attempts to loosen the bond between lice eggs and hair to facilitate nit removal via a fine tooth comb. STEP 2.RTM. has a formic acid base which is a harsh chemical and produces an unpleasant odor. It also contains polyquaternium, benzyl alcohol and cetyl alcohol as preservatives. However, contrary to the claims made by the manufacturer of STEP 2.RTM., it has been determined by the present inventor that STEP 2.RTM. does not provide any practical ability to loosen nits to facilitate removal by combing. Finally, STEP 2.RTM. does not break down pesticidal shampoo toxins.
The present invention, however, does satisfactorily remove lice eggs from hair stands. When used as a post-pediculicide treatment it is capable of removing pediculicide product residue and the odor associated therewith to leave treated hair clean and fresh smelling. It uses a water-based enzyme composition that attacks the cement-like complex organic structure that bonds the nit to the hair causing swelling and/or biodegrading of the complex organic structure to facilitate the subsequent physical removal of the lice nits from the hair. When it acts as a biodegrader it converts the complex organic structure to another non-bonding composition, e.g., a sugar. As such, it is a natural, vegetable derived enzyme, chemical-free and non-toxic composition which attacks and rapidly swells and/or biodegrades the complex organic structure that comprises the louse glue. Moreover, the water-based enzyme composition of the present invention is effective in breaking chemical bonds, resulting in the biodegrading of pediculicide residues on the hair and scalp of the patient. Furthermore, the water-based enzyme composition does not react to the protein structure of the hair and it is non-irritating to the skin and mucous membranes. It also leaves the treated hair soft, silky and fresh smelling.
The present invention also provides many additional advantages which shall become apparent as described below.